Disease Tolerance and Pathogen Resistance Genes May Underlie Trypanosoma cruzi Persistence and Differential Progression to Chagas Disease Cardiomyopathy

• Published in: Frontiers in immunology 2018-12, Vol.9, p.2791
• Main Authors: Chevillard, Christophe, Nunes, João Paulo Silva, Frade, Amanda Farage, Almeida, Rafael Ribeiro, Pandey, Ramendra Pati, Nascimento, Marilda Savóia, Kalil, Jorge, Cunha-Neto, Edecio
• Format: Article
• Language: English
• Subjects: Adaptive immunology; Biochemistry, Molecular Biology; chagas cardiomyopathy; Chagas Cardiomyopathy - immunology; Chagas Disease - immunology; Disease Progression; disease tolerance gene; Genetics; Heart - parasitology; Human genetics; Humanities and Social Sciences; Humans; Immune Tolerance - immunology; Immunology; interferon gamma; Interferon-gamma - immunology; Interleukin-10 - immunology; Life Sciences; Microbiology and Parasitology; Parasitology; pathogen resistance genes; Th1 Cells - immunology; Th1 Cells - parasitology; Tripanosoma cruzi; Trypanosoma cruzi - immunology
• ISSN: 1664-3224; 1664-3224
• DOI: 10.3389/fimmu.2018.02791

Chagas disease is caused by infection with the protozoan and affects over 8 million people worldwide. In spite of a powerful innate and adaptive immune response in acute infection, the parasite evades eradication, leading to a chronic persistent infection with low parasitism. Chronically infected subjects display differential patterns of disease progression. While 30% develop chronic Chagas disease cardiomyopathy (CCC)-a severe inflammatory dilated cardiomyopathy-decades after infection, 60% of the patients remain disease-free, in the asymptomatic/indeterminate (ASY) form, and 10% develop gastrointestinal disease. Infection of genetically deficient mice provided a map of genes relevant for resistance to infection, leading to the identification of multiple genes linked to survival to infection. These include pathogen resistance genes (PRG) needed for intracellular parasite destruction, and genes involved in disease tolerance (protection against tissue damage and acute phase death-DTG). All identified DTGs were found to directly or indirectly inhibit IFN-γ production or Th1 differentiation. We hypothesize that the absolute need for DTG to control potentially lethal IFN-γ PRG activity leads to persistence and establishment of chronic infection. IFN-γ production is higher in CCC than ASY patients, and is the most highly expressed cytokine in CCC hearts. Key DTGs that downmodulate IFN-γ, like IL-10, and Ebi3/IL27p28, are higher in ASY patients. Polymorphisms in PRG and DTG are associated with differential disease progression. We thus hypothesize that ASY patients are disease tolerant, while an imbalance of DTG and IFN-γ PRG activity leads to the inflammatory heart damage of CCC.